Thyroid function test changes with adjuvant tamoxifen therapy in postmenopausal women with breast cancer.

PURPOSE: While tamoxifen has been shown to alter concentration of many hormones and their binding globulins, there have been conflicting results regarding its effects on thyroid function tests. We sought to clarify these effects by studying subjects in a controlled clinical trial. PATIENTS AND METHODS: We evaluated a subset of postmenopausal women who had participated in a longitudinal, double-blind, randomized, placebo-controlled toxicity study of tamoxifen 10 mg orally, twice daily. There were 14 subjects in both the tamoxifen and placebo groups. Measurement of thyroid-binding globulin (TBG), thyroxine uptake (T-Uptake), thyroxine (T4), and thyroid-stimulating hormone (TSH), and an indirect estimate of the free T4 index (FTI), were made for each subject before and after 3 months of treatment. RESULTS: For T-Uptake, T4, and TBG, there were significant increases in the mean change from baseline to 3 months in the tamoxifen group compared with the placebo group (P = .02, .0001, and .003, respectively), while there were no significant changes in the measured TSH and in the calculated FTI. CONCLUSION: We conclude that tamoxifen therapy in postmenopausal women results in increased TBG, with secondary increases in measured T-Uptake and T4 following. However, TSH and FTI levels are unchanged, and treated women remain eumetabolic.

Protein S and protein C level changes with adjuvant tamoxifen therapy in postmenopausal women.

Tamoxifen citrate is a synthetic antiestrogen that provides survival benefit when given as adjuvant treatment in postmenopausal women with breast cancer. Venous thrombophlebitis may complicate tamoxifen treatment at a rate of approximately one per 800 treatment-years. To explore the possible procoagulant effects associated with tamoxifen therapy we evaluated changes in protein S and C activity levels in 58 postmenopausal women with surgically resected breast cancer who were disease-free and participating in a double-blind, placebo-controlled, randomized toxicity study of tamoxifen. The changes in protein C activities for the tamoxifen group (mean level = 113%) compared to those in the placebo group (mean level = 115%) were not significant (p = 0.45). Protein S activity levels increased while protein C activity levels decreased from baseline at 24 months in both tamoxifen and placebo groups. We conclude that the possible thrombophlebitis-promoting effect of tamoxifen in postmenopausal women is unlikely to be explained on the basis of protein S and protein C activity level changes.

Metastatic breast cancer 39 years after primary treatment.

The appearance of metastatic disease decades after primary treatment for cancers occurs rarely with cancers of the breast, malignant melanoma, and cancers of the kidney. Certainty about the relationship of primary and metastatic cancers is often limited by the absence of tissues showing identical histology, omission of various procedures and tests ruling out a new primary cancer, and follow-up data with treatment which supports the case for late recurrence. We report here the unusual case of an 84-year-old woman initially treated with mastectomies for a benign breast condition at age 39 and invasive breast adenocarcinoma at age 44. A pleural effusion developed at age 83 which showed adenocarcinoma. Physical examination and an extensive evaluation were unrevealing. Hormonal treatment has sustained remission of disease for 1 year.